The Kv3 voltage-gated potassium channel family includes four members, Kv3.1, Kv3.2, KV3.3, and Kv3.4. Genes for each of these subtypes can generate multiple isoforms by alternative splicing, producing versions with different C-terminal domains. Thirteen isoforms have been identified in mammals to date, but the currents expressed by these variants appear identical (Rudy and McBain, 2001, Trends in Neurosciences 24, 517-526). Kv3 channels are activated by depolarisation of the plasma membrane to voltages more positive than −20 mV; furthermore, the channels deactivate rapidly upon repolarisation of the membrane. These biophysical properties ensure that the channels open towards the peak of the depolarising phase of the neuronal action potential to initiate repolarisation. Rapid termination of the action potential mediated by Kv3 channels allows the neuron to recover more quickly to reach sub-threshold membrane potentials from which further action potentials can be triggered. As a result, the presence of Kv3 channels in certain neurons contributes to their ability to fire at high frequencies (Rudy and McBain, 2001, Trends in Neuroses. 24, 517-526). Kv3.13 subtypes are predominant in the CNS, whereas Kv3.4 channels are found predominantly in skeletal muscle and sympathetic neurons (Weiser et al., 1994, J. Neurosci. 14, 949-972). Kv3.1-3 channel subtypes are differentially expressed by sub-classes of interneurons in cortical and hippocampal brain areas (e.g. Chow et al., 1999, J. Neurosci. 19, 9332-9345; Martina et al., 1998, J. Neurosci. 18, 8111-8125; McDonald and Mascagni, 2006, Neuroses. 138, 537-547, Chang et al., 2007, J. Comp. Neurol. 502, 953-972), in the thalamus (e.g. Kasten et al., 2007, J. Physiol. 584, 565-582), cerebellum (e.g. Sacco et al., 2006, Mol. Cell. Neuroses. 33, 170-179), and auditory brain stem nuclei (Li et al., 2001, J. Comp. Neurol. 437, 196-218).
Characterisation of mice in which one or more of the Kv3 subtypes has been deleted shows that the absence of Kv3.1 gives rise to increased locomotor activity, altered electroencephalographic activity, and a fragmented sleep pattern (Joho et al., 1999, J. Neurophysiol. 82, 1855-1864). The deletion of Kv3.2 leads to a reduction in seizure threshold and altered cortical electroencephalographic activity (Lau et al., 2000, J. Neurosci. 20, 9071-9085). Deletion of Kv3.3 is associated with mild ataxia and motor deficits (McMahon et al., 2004, Eur. J. Neurosci. 19, 3317-3327). Double deletion of Kv3.1 and Kv3.3 gives rise to a severe phenotype characterised by spontaneous seizures, ataxia, and an increased sensitivity to the effects of ethanol (Espinosa et al., 2001, J. Neurosci. 21, 6657-8865; Espinosa et al., 2008, J. Neurosci. 28, 5570-5581).
The known pharmacology of Kv3 channels is limited. Tetraethylammonium (TEA) has been shown to inhibit the channels at low millimolar concentrations (Rudy and McBain, 2001, Trends in Neuroses. 24, 517-526), and blood-depressing substance (BDS) toxins from the sea anemone, Anemonia sulcata (Diochot et al., 1998, J. Biol. Chem. 273, 6744-6749), have been shown to selectively inhibit Kv3 channels with high affinity (Yeung et al., 2005, J. Neurosci. 25, 8735-8745). In addition to compounds acting directly on Kv3 channels, agonists of receptors that activate protein kinase A (PKA) and protein kinase C (PKG) have been shown to modulate Kv3-mediated currents in specific brain areas, leading to a reduction in the ability of the neurons to fire at high frequency (Aizoh et al., 2000, Nat. Neurosci. 3, 791-798; Song et al., 2005, Nat Neurosci. 8, 1335-1342); these studies suggest that PKA and RKC can specifically phosphorylate Kv3 channels in a neuron-specific manner, causing a reduction in Kv3-mediated currents. There are no descriptions in the literature of compounds or biochemical mechanisms that positively modulate or activate Kv3 channels.
Bipolar disorder, schizophrenia, anxiety, and epilepsy are serious disorders of the central nervous system that have been associated with reduced function of inhibitory interneurons and gamma-amino butyric acid (GABA) transmission (Reynolds et al., 2004, Neurotox. Res. 6, 57-61; Benes et al., 2008, RNAS, 105, 20935-20940; Brambiila et al., 2003, Mol. Psychiatry. 8, 721-37, 715; Aroniadou-Anderjaska et al., 2007, Amino Acids 32, 305-315; Ben-Ari, 2006, Grit. Rev. Neurobiol. 18, 135-144). Rarvalbumin positive basket cells that express Kv3 channels in the cortex and hippocampus play a key role in generating feedback inhibition within local circuits (Markram et al., 2004, Nat. Rev. Neurosci. 5, 793-807). Given the relative dominance of excitatory synaptic input over inhibitory input to glutamatergic pyramidal neurons in these circuits, fast-firing of interneurons supplying inhibitory input is essential to ensure balanced inhibition. Furthermore, accurate timing of inhibitory input is necessary to sustain network synchronisation, for example, in the generation of gamma frequency field potential oscillations that have been associated with cognitive function (Fisahn et al., 2005, J. Physiol 562, 65-72; Engel et al., 2001, Nat. Rev. Neurosci. 2, 704-718). Notably, a reduction in gamma oscillations has been observed in patients with schizophrenia (Spencer et al., 2004, RNAS 101, 17288-17293). Consequently, positive modulators of Kv3 channels might be expected to enhance the firing capabilities of specific groups of fast-firing neurons in the brain. These effects may be beneficial in disorders associated with abnormal activity of these neuronal groups.
In addition, Kv3.2 channels have been shown to be expressed by neurons of the superchiasmatic nucleus (SCN) the main circadian pacemaker in the CNS (Schulz and Steimer, 2009, CNS Drugs 23 Suppl 2, 3-13). We have shown that the expression of Kv3.2 channels varies over a 24 hour period; thus Kv3.2 channel expression may contribute to changes in the firing properties of neurons in the SCN and thus influence circadian rhythm. Consequently, drugs that modulate the activity of Kv3.2 channels could influence circadian rhythm and thus be useful in the treatment of related disorders.
Hearing loss represents an epidemic that affects approximately 16% of the population in Europe and the US (Goldman and Holme, 2010, Drug Discovery Today 15, 253-255), with a prevalence estimated at 250 million people worldwide (B. Shield, 2006, Evaluation of the social and economic costs of hearing impairment. A report for Hear-It AISBL: www.hear-it.org/multimedia/Hear It Report October 2006.pdf). As life expectancy continues to increase, so too will the number of people suffering from hearing disorders. Furthermore, it is believed that modern lifestyles may exacerbate this burden as the younger generation ages. Hearing conditions, including tinnitus have a profound effect on the quality of life, causing social isolation, depression, work and relationship difficulties, low self-esteem, and prejudice. Voltage-gated ion channels of the Kv3 family are expressed at high levels in auditory brainstem nuclei (Li et al., 2001, J. Comp. Neurol. 437, 196-218) where they permit the fast firing of neurons that transmit auditory information from the cochlear to higher brain regions. Loss of Kv3.1 channel expression in central auditory neurons is observed in hearing impaired mice (von Hehn et al., 2004, J. Neurosci. 24, 1938-1940), and a decline in Kv3.1 expression may be associated with loss of hearing in aged mice (Jung et al. 2005 Neurol, Res. 27, 436-440). Furthermore, pathological plasticity of auditory brainstem networks is likely to contribute to symptoms of tinnitus that are experienced by many people suffering from hearing loss of different types. Recent studies have shown that regulation of Kv3.1 channel function and expression has a major role in controlling auditory neuron excitability (Kaczmarek et al., 2005, Hearing Res. 206, 133-145), suggesting that this mechanism could account for some of the plastic changes that give rise to tinnitus. Finally, Fragile X syndrome and autism are frequently associated with hypersensitivity to sensory input, including auditory stimuli. Recent findings suggest that the protein coded by the FMR-I gene, whose mutation or absence gives rise to Fragile X syndrome, may directly regulate the expression of Kv3.1 channels in the auditory brainstem nuclei (Strumbos et al., 2010, J. Neuroscience, in press), suggesting that mis-reguiation of Kv3.1 channels could give rise to hyperacusis in patients suffering from Fragile X or autism. Consequently, we propose that small molecule modulators of Kv3 channels in auditory brainstem nuclei could have a benefit in the treatment of disorders of hearing, including tinnitus and auditory hyper-acuity associated with Fragile X syndrome and autism.
In a first aspect therefore, the invention provides a compound of formula (Ia)

wherein:
R1 is halo, C1-4 alkyl, C1-4 alkoxy, halo-C1-4-alkyl, halo-C1-4alkoxy, or cyano;
R2 is H, halo, cyano, C1-4 alkyl or C1-4 alkoxy; with the proviso that when R2 is H, R1 is not in the para position;
X is C or N;
Y is C or N;
R3 is C1-4 alkyl;
R4 is H, deuterium, or C1-4alkyl; or R3 and R4 can be fused to form a C3-4 spiro carbocyclyl group;
or a pharmaceutically acceptable salt thereof.
In a second aspect the invention provides a compound of formula (Ib)

wherein:
R1 is halo, C1-4 alkyl or C1-4 alkoxy, halo-C1-4alkoxy, cyano;
R2 is H, halo, C1-4 alkyl and C1-4 alkoxy; with the proviso that when R2 is H, R1 is not in the para position;
X is G or N;
Y is C or N;
R3 is C1-4 alkyl;
R4 is H, deuterium, C1-4alkyl; or R3 and R4 can be fused to form a C3-4 spiro carbocycly group;
or a pharmaceutically acceptable salt thereof.
In a third aspect therefore, the invention provides a compound of formula (Ic)

wherein:
R1 is halo, C1-4 alkyl or C1-4 alkoxy;
R2 is H, halo, C1-4 alkyl and C1-4 alkoxy; with the proviso that when R2 is H, R1 is not in the para position;
X is C or N;
Y is C or N;
R3 is C1-4 alkyl; is H, deuterium, C1-4alkyl; or R3 and R4 can be fused to form a C3-4 spiro carbocycly group;
or a pharmaceutically acceptable salt thereof.
As used herein below, “Formula (I)” means any one of Formula (Ia), (Ib), or (Ic).
In one embodiment of the invention R1 is C1-4 alkoxy. In another embodiment of the invention R1 is methoxy.
In one embodiment of the invention R1 is C1-4 alkyl. In another embodiment of the invention R1 is methyl. In a further embodiment of the invention R1 is ethyl. In a yet further embodiment of the invention R1 is propyl, in a yet further embodiment of the invention R1 is butyl.
In one embodiment of the invention R1 is halo. In another embodiment of the invention R1 is chloro. In a further embodiment of the invention R1 is fluoro.
In one embodiment of the invention R1 is halo-C1-4alkoxy. In another embodiment of the invention R1 is trifluoromethoxy.
In one embodiment of the invention R1 is halo-C1-4alkyl. In another embodiment of the invention R1 is trifluoromethyl.
In one embodiment of the invention R1 is cyano.
In one embodiment of the invention, R2 is H.
In one embodiment of the invention R2 is C1-4alkyl. In another embodiment of the invention R2 is methyl.
In one embodiment of the invention R2 is halo. In another embodiment of the invention, R2 is chloro, in a further embodiment of the invention R2 is fluoro.
In one embodiment of the invention R2 is C1-4 alkyl.
In one embodiment of the invention R2 is cyano.
In one embodiment of the invention X is C and Y is C.
In one embodiment of the invention X is N and Y is C.
In one embodiment of the invention X is N and V is N.
In one embodiment of the invention R3 is methyl, in another embodiment of the invention R3 is ethyl, in a further embodiment of the invention R3 is propyl. In a yet further embodiment of the invention R3 is butyl.
In one embodiment of the invention R4 is H.
In one embodiment of the invention R4 is deuterium.
In one embodiment of the invention R4 is C1-4 alkyl. In another embodiment of the invention R4 is methyl.
In one embodiment of the invention R3 and R4 together form a C3-4 spiro carbocyl. In anther embodiment of the invention R3 and R4 together form a C3 spiro carbocycyl. In a further embodiment of the invention R3 and R4 together form a C4 spiro carbocycyl.
In one embodiment of the invention R3 is C1-4 alkyl, R4 is H and the absolute configuration of the stereogenic centre is R.
In one embodiment of the invention R1 is C1-4alkyl, C1-4 alkoxy, or halo-C1-4 alkoxy; R2 is H, cyano or alkyl; X is N, Y is N or C, R3 is C1-4 alkyl, and R4 is C1-4 alkyl or H; or a pharmaceutically acceptable salt thereof.
In one embodiment of the invention R, is propyl, butyl, methoxy, propoxy, or trifluoromethoxy; R2 is H, cyano or methyl; X is N, Y is N or C, Ra is ethyl, and R4 is methyl or H; or a pharmaceutically acceptable salt thereof.
In one embodiment of the invention R1 is methoxy and R2 is methyl. In another embodiment of the invention R1 is methoxy in the meta position and R2 is methyl in the para position, in a further embodiment of the invention R1 is methoxy in the meta position, R2 is methyl in the para position, R3 is C1-4 alkyl, R4 is H, R3 is in the R configuration. In a yet further embodiment of the invention R1 is methoxy in the meta position, R2 is methyl in the para position, X is N, Y is G, R3 is CM alkyl, R4 is H and the absolute configuration of the stereogenic centre is R. In a still further embodiment of the invention R1 is methoxy in the meta position, R2 is methyl in the para position, X is N, Y is C, R3 is ethyl, R4 is H and the absolute configuration of the stereogenic centre is R.
In one embodiment of the invention the compound is selected from the group consisting of:    (5R)-5-methyl-3-{4-[(3-methylphenyl)oxy]phenyl}-2,4-imidazolidinedione:    (5R)-5-methyl-3-(4-{[3-(methyloxy)phenyl]oxy}phenyl)-2,4-imidazolidinedione;    (5R)-3-(4-{[3-(ethyloxy)phenyl]oxy}phenyl)-5-methyl-2,4-imidazolidinedione;    (5R)-3-{4-[(3-chloro-5-fluorophenyl)oxy]phenyl}-5-methyl-2,4-imidazolidinedione;    (5R)-3-{4-[(3-chloro-4-fluorophenyl)oxy]phenyl}-5-methyl-2,4-imidazolidinedione;    (5S)-3-{4-[(3-chloro-4-fluorophenyl)oxy]phenyl}-5-methyl-2,4-imidazolidinedione;    (5R)-5-methyl-3-(4-{[2-methyl-5-(methyloxy)phenyl]oxy}phenyl)-2,4-imidazolidinedione;    (5R)-5-methyl-3-(4-{[4-methyl-3-(methyloxy)phenyl]oxy}phenyl)-2,4-imidazolidinedione;    (5R)-5-methyl-3-(6-{[3-(1-methylethyl)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-methyl-3-[6-({3-[(1-methylethyl)oxy]phenyl}oxy)-3-pyridinyl]-2,4-imidazolidinedione;    (5R)-3-{6-[(2,5-dimethylphenyl)oxy]-3-pyridinyl}-5-methyl-2,4-imidazolidinedione;    (5R)-3-{6-[(2,3-dimethylphenyl)oxy]-3-pyridinyl}-5-methyl-2,4-imidazolidinedione;    (5R)-3-{6-[(2,6-dimethylphenyl)oxy]-3-pyridinyl}-5-methyl-2,4-imidazolidinedione;    (5R)-3-{6-[(2-ethylphenyl)oxy]-3-pyridinyl}-5-methyl-2,4-imidazolidinedione;    (5R)-5-methyl-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-methyl-3-(6-{[2-methyl-5-(methyloxy)phenyl]-oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-methyl-3-(6-{[2-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-ethyl-3-(4-{[3-(methyloxy)phenyl]oxy}phenyl)-2,4-imidazolidinedione;    (5R)-5-ethyl-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5S)-5-ethyl-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-ethyl-3-(6-{[3-(1-methylethyl)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    5,5-dimethyl-3-(4-{[3-(methyloxy)phenyl]oxy}phenyl)-2,4-imidazolidinedione;    3-{4-[(2,3-dimethylphenyl)oxy]phenyl}-5,5-dimethyl-2,4-imidazolidinedione;    3-{6-[(2-ethylphenyl)oxy]-3-pyridinyl}-5,5-dimethyl-2,4-imidazolidinedione;    3-{6-[(2,6-dimethylphenyl)oxy]-3-pyridinyl}-5,5-dimethyl-2,4-imidazolidinedione;    (5R)-5-(1-methylethyl)-3-(4-{[4-methyl-3-(methyloxy)phenyl]oxy}phenyl)-2,4-imidazolidinedione;    (5R)-5-methyl-3-(2-{[3-(1-methylethyl)phenyl]oxy}-5-pyrimidinyl)-2,4-imidazolidinedione;    (5R)-5-ethyl-3-(2-{[3-(ethyloxy)-4-methylphenyl]oxy}-5-pyrimidinyl)-2,4-imidazolidinedione;    (5R)-5-(1,1-dimethylethyl)-3-(6-{[4-methyl-3-{methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-ethyl-5-methyl-3-(6-{[4-methyl-3-(methyloxy}phenyl]-oxy}-3-pyridinyl)-2,4-imidazolidinedione;    7-(8-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-5,7-diazaspiro[3.4]octane-6,8-dione;    6-(8-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-4,6-diazaspiro[2.4]heptane-5,7-dione;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-2-(1-methylethyl)benzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-2-[(trifluoromethyl)oxy]benzonitrile;    3-{6-[(4-fluoro-3-methylphenyl)oxy]-3-pyridinyl}-5,5-dimethyl-2,4-imidazolidinedione;    3-{6-[(4-fluoro-2-methylphenyl)oxy]-3-pyridinyl}-5,5-dimethyl-2,4-imidazolidinedione;    5,5-dimethyl-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    (5R)-5-(1-methylethyl)-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    3-(6-{[2-(1,1-dimethylethyl)phenyl]oxy}-3-pyridinyl)-5,5-dimethyl-2,4-imidazolidinedione;    3-(2-{[2-{1,1-dimethylethyl}phenyl]oxy}-5-pyrimidinyl)-5,5-dimethyl-2,4-imidazolidinedione;    (5R)-5-ethyl-5-methyl-3-(2-{[4-methyl-3-(methyloxy)phenyl]oxy}5-pyrimidinyl)-2,4-imidazolidinedione;    (5R)-5-ethyl-3-(2-{[3-(ethyloxy)-4-methylphenyl]oxy}-5-pyrimidinyl)-5-methyl-2,4-imidazolidinedione;    5,5-dimethyl-3-[6-({3-[(trifluoromethyl)oxy]phenyl}oxy)-3-pyridinyl]-2,4-imidazolidinedione;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-3-ethylbenzonitrile;    2-chloro-4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}benzonitrile;    5,5-dimethyl-3-[6-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-3-pyridinyl]-2,4-imidazolidinedione;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-2-(methyloxy)benzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-3-methylbenzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-3-(trifluoromethylbenzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-2-ethylbenzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyrimidinyl]oxy}-2-ethylbenzonitrile;    3-cyclopropyl-4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}benzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-3-(1,1-dimethylethyl)benzonitrile;    2-[(cyclopropylmethyl)oxy]-4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}benzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-t-imidazolidinyl)-2-pyridinyl]oxy}-2-(ethyloxy)benzonitrile;    2-cyclopropyl-4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}benzonitrile;    5,5-dimethyl-3-[2-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-5-pyrimidinyl]-2,4-imidazolidinedione;    4-{[5′(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyrimidinyl]oxy}-3-(1,1-dimethylethyl)benzonitrile;    4-{[5-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)-2-pyridinyl]oxy}-2-[(1-methylethyl)oxy]benzonitrile;    4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-[(1-methylethyl)oxy]benzonitrile;    3-cyclopropyl-4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyradinyl}oxy)-2-[(trifluoromethyl)oxy]benzonitrile;    2-cyclopropyl-4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    (5R)-5-ethyl-5-methyl-3-[2-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-5-pyrimidinyl]-2,4-imidazolidinedione;    3-(1,1-dimethylethyl)-4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyrimidinyl}oxy)benzonitrile;    3-(1,1-dimethylethyl)-4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    4-{[4-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)phenyl]oxy}-2-(methyloxy)benzonitrile;    4-{[4-(4,4-dimethyl-2,5-dioxo-1-imidazolidinyl)phenyl]oxy}-2-(ethyloxy)benzonitrile;    4-({4-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]phenyl}oxy)-2-(ethyloxy)benzonitrile;    3-cyclopropyl-4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    3-(1,1-dimethylethyl)-4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(methyloxy)benzonitrile;    4-({4-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]phenyl}oxy)-2-(methyloxy)benzonitrile;    2-[(cyclopropylmethyl)oxy]-4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    (5R)-5-ethyl-3-[6-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-3-pyridinyl]-2,4-imidazolidinedione;    2-cyclopropyl-4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(1-methylethyl)benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(1-methylethyl)benzonitrile;    (5R)-5-ethyl-3-[2-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-5-pyrimidinyl]-2,4-imidazolidinedione;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-[(1-methylethyl)oxy]benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-3-methylbenzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-[(trifluoromethyl)oxy]benzonitrile;    3-ethyl-4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyrimidinyl}oxy)benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyrimidinyl}oxy)-3-methylbenzonitrile;    3-(1,1-dimethylethyl)-4-({5-[(4R)-4-ethyl-2,5-dioxo-1 imidazolidinyl]-pyrimidinyl}oxy)benzonitrile and    4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(1-methylethyl)benzonitrile or
a pharmaceutically acceptable salt thereof.
In one embodiment of the invention, the compound is selected from the group consisting of:    (5R)-5-ethyl-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl;    (5R)-5-ethyl-5-methyl-3-(6-{[4-methyl-3-(methyloxy)phenyl]oxy}-3-pyridinyl)-2,4-imidazolidinedione;    4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-[(trifluoromethyl)oxy]benzonitrile;    (5R)-5-ethyl-5-methyl-3-[2-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-5-pyrimidinyl]-2,4-imidazolidinedione;    3-(1,1-dimethylethyl)-4-({5-[(4R)-4-ethyl-4-methyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)benzonitrile;    (5R)-5-ethyl-3-[6-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-3-pyridinyl]-2,4-imidazolidinedione;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(1-methylethyl)benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-(1-methylethyl)benzonitrile;    (5R)-5-ethyl-3-[2-({4-methyl-3-[(trifluoromethyl)oxy]phenyl}oxy)-5-pyrimidinyl]-2,4-imidazolidinedione;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-[(1-methylethyl)oxy]benzonitrile;    4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyridinyl}oxy)-2-[(trifluoromethyl)oxy]benzonitrile;    3-(1,1-dimethylethyl)-4-({5-[(4R)-4-ethyl-2,5-dioxo-1-imidazolidinyl]-2-pyrimidinyl}oxy)benzonitrile;
or a pharmaceutically acceptable salt thereof.
For the avoidance of doubt, the embodiments of any one feature of the compounds of the invention may be combined with any embodiment of another feature of compounds of the invention to create a further embodiment.
The term ‘halo’ or ‘halogen’ as used herein, refers to a fluorine, chlorine, bromine or iodine atom.
When the compound contains a (C1-4)alkyl group, whether alone or forming part of a larger group, e.g. (C1-4)alkoxy, the alkyl group may be straight chain, branched, cyclic, or a combination thereof. Examples of (C1-4)alkyl are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl and cyclobutyl. An example of (C1-4)alkoxy is methoxy. An example of halo-C1-4alky is trifluoromethyl. An example of halo-C1-4alkoxy is trifiuromethoxy.
It will be appreciated that for use in medicine the salts of the compounds of formula (I) should be pharmaceutically acceptable. Suitable pharmaceutically acceptable salts will be apparent to those skilled in the art. Pharmaceutically acceptable salts include those described by Berge, Bighley and Monkhouse J. Pharm. Sci (1977) 86, pp 1-19. Such pharmaceutically acceptable salts include acid addition salts formed with inorganic acids e.g. hydrochoric, hydrobromic, sulphuric, nitric or phosphoric acid and organic acids e.g. succinic, maleic, acetic, fumaric, citric, tartaric, benzoic, p-toluenesulfonic, methanesulfonic or naphthalenesulfonic acid. Other salts e.g. oxalates or formates, may be used, for example in the isolation of compounds of formula (I) and are included within the scope of this invention.
Certain of the compounds of formula (I) may form acid addition salts with one or more equivalents of the acid. The present invention includes within its scope all possible stoichiometric and non-stoichiometric forms.
The compounds of formula (I) may be prepared in crystalline or non-crystalline form and, if crystalline, may optionally be solvated, eg, as the hydrate. This invention includes within its scope stoichiometric solvates (eg. hydrates) as well as compounds containing variable amounts of solvent (eg. water).
It will be understood that the invention includes pharmaceutically acceptable derivatives of compounds of formula (I) and that these are included within the scope of the invention.
As used herein “pharmaceutically acceptable derivative” includes any pharmaceutically acceptable ester or salt of such ester of a compound of formula (I) which, upon administration to the recipient is capable of providing (directly or indirectly) a compound of formula (i) or an active metabolite or residue thereof.
It is to be understood that the present invention encompasses all isomers of formula (I) and their pharmaceutically acceptable derivatives, including ail geometric, tautomeric and optical forms, and mixtures thereof (e.g. racemic mixtures). Where additional chiral centres are present in compounds of formula (I), the present invention includes within its scope all possible diastereoismers, including mixtures thereof. The different isomeric forms may be separated or resolved one from the other by conventional methods, or any given isomer may be obtained by conventional synthetic methods or by stereospecific or asymmetric syntheses.
The subject invention also includes isotopically-labeled compounds which are identical to those recited in formula (I) but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number most commonly found in nature. Examples of isotopes that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, fluorine, iodine and chlorine such as 3H, 11C, 14C, 18F, 123I or 125I.
Compounds of the present invention and pharmaceutically acceptable salts of said compounds that contain the aforementioned isotopes and/or other isotopes of other atoms are within the scope of the present invention. Isotopically labeled compounds of the present invention, for example those into which radioactive isotopes such as 3H or 14C have been incorporated, are useful in drug and/or substrate tissue distribution assays. Tritiated, ie. 3H, and carbon-14, ie. 14C, isotopes are particularly preferred for their ease of preparation and detectability. 11C and 18F isotopes are particularly useful in PET (positron emission tomography).
Since the compounds of formula (I) are intended for use in pharmaceutical compositions it will readily be understood that they are each preferably provided in substantially pure form, for example at least 60% pure, more suitably at least 75% pure and preferably at least 85%, especially at least 98% pure (% are on a weight for weight basis), impure preparations of the compounds may be used for preparing the more pure forms used in the pharmaceutical compositions.
According to a further aspect of the present invention there is provided a process for the preparation of compounds of formula (I) and derivatives thereof. The following schemes detail some synthetic routes to compounds of the invention. In the following schemes reactive groups can be protected with protecting groups and deprotected according to well established techniques.
In general, the compounds of formula (I) may be made according to the organic synthesis techniques known to those skilled in this field, as well as by the representative methods set forth in the Examples.
Compounds of formula (I), and salts and solvates thereof, may be prepared by the general methods outlined hereinafter. In the following description, the groups R1, R2, X, Y, R3, R4 have the meanings as previously defined for compounds of formula (I) unless otherwise stated.

Step (ii):
Compounds of formula (I) can be prepared by cyclization of compounds of formula (II) in a solvent e.g. dichloromethane with a carbonylating agent e.g. triphosgene preferentially prediluted in the same solvent and added in a second time at 0° C. in presence of a base e.g. triethylamine. In some cases ethyl acetate could be used as a solvent. Optionally a catalytic amount of DMAP can be added.
Step (i):
Compounds of formula (II) can be prepared from compounds of formula (III) by removal of the BOG protective group in acidic conditions e.g. TFA in a solvent e.g., dichloromethane e.g. at 0° C., RT.

Step (ii):
compounds of formula (iii) can be prepared from anilines of formula (iv) and N-protected amino acids of formula (V) by amidic coupling in presence of a base e.g. DIPEA and of a coupling agent e.g. HATU, TBTU, HBTU in a solvent such as N,N-dimethylformamide.
Step (i):
Some N-Boc protected amino acids of formula (V) are commercially available e.g. N-{[(1,1-dimethylethyl)oxy]carbonyl}-2-methylalanine from for example Aldrich, N-{[(1,1-dimethylethyl)oxy]carbonyl}-D-alanine from for example Aldrich, (2R)-2-({[(1,1-dimethylethyl)oxy]carbonyl}amino)butanoic acid from for example Bachem UK Ltd, N-{[(1,1-dimethylethyl)oxy]carbonyl}-D-isovaline from for example Nagase & Co Ltd.
N-protected amino acids of formula (V) can also be prepared from compounds of formula (VI) for example with Boc-anhydride in presence of a base e.g. aqueous NaHCO3, aqueous sodium hydroxide in a solvent such as THF, methanol, dioxane. Many descriptions are available in the literature (for example Tetrahedron, 2006, 62(42), 9966-9972)

Some anilines (IV) are commercially available, e.g. 4-{[3-(methyloxy)phenyl]oxy}aniline for example from ChemBridge Corporation.
Other anilines can be prepared from the nitro compounds (VII). Suitable reactions conditions to transform (VII) into (IV) are for example:                reduction in presence of Fe powder and ammonium chloride in a solvent such as ethanol or a mixture THF/water with heating or not        reduction in presence of Zn powder and ammonium chloride in a solvent such as ethanol or a mixture THF/water with heating or not        reduction with tin chloride hydrate in a solvent such as ethyl acetate, ethanol with heating for example at reflux        

Anilines of formula (IVa), wherein R1 is (C1-4 alkyl or C1-4 alkoxy), R2 is (H, C1-4 alkyl or C1-4 alkoxy) and (X,Y)≠(N,N) can be prepared from the nitro compounds (Vila) with the conditions described on scheme 3 or with the following conditions:                hydrogenation with H2 with a catalyst such as Pd/G in a solvent such as methanol, ethanol, THF, a mixture methanol/ethyl acetate with heating or not        reduction with hydrazine hydrate and a catalytic amount of Pd/G in a solvent such as ethanol with heating        

Compounds of formula (VIIb) wherein X═Y═C or (X═C, Y═N) or (X═N, Y═C) can be prepared by nucleophilic aromatic substitution. In this reaction are used a nitro derivative of formula (VIIIb) wherein Z═F (usually when [X═C, Y═C]) or Z═Cl (usually when [X═N, Y═C] or [X═C, Y═N]) and a phenol of formula (IX) in presence of a base in a solvent such as                potassium carbonate e.g. in N,N-dimethylformanilide or in acetonitrile with regular heating or microwave one        potassium tertiary-butoxide e.g. in DMSO,        sodium hydride e.g. in N,N-dimethylformamide with a regular heating e.g. at reflux or with a microwave irradiation. Optionally, before addition of the nitro derivative (VIII), the phenol (IX) can be pre-stirred in presence of the solvent and the base.        
Compounds of formula (Vile) wherein X═Y═N can be prepared by nucleophilic aromatic substitution from phenol (IX) and nitro compound (VIIIc) wherein usually Z=GI.
The base use is for example                potassium carbonate e.g. in N,N-dimethylformamide or acetonitrile at room temperature        triethylamine e.g. in acetonitrile at reflux        

Phenols of formula (iXa), wherein R1 and R2 are groups compatible with typical nitrosation conditions, can be prepared using the corresponding anilines (X) with sodium nitrite in presence of an excess of acid such as sulphuric acid in a solvent such as water, at 0° C. or 0° C.-5° C. in a first time and under heating in a second time e.g. at 40° C.-90° C.

Anilines of formula (Xa) (wherein R1 and R2 are groups non sensitive to typical nitrosation conditions) can be prepared from the nitro derivatives of formula (XI) (wherein R1 and R2 are groups non sensitive to typical nitrosation conditions) using usual reduction conditions for example                hydrogenation with H2 in a solvent, such as methanol in presence of a metal catalyst such as Raney Nickel or Pd/C typically at room temperature.        reduction in presence of Fe powder and ammonium chloride in a solvent such as a mixture THF wafer or ethanol for example at room temperature.        

Some nitro derivatives of formula (XI) are commercially available.
Some other nitro derivatives such as the compound of formula (XIa) wherein R2 is an ethoxy group can be prepared from the corresponding nitrophenol derivative of formula (XII) by alkylation with for example ethyl iodide in presence of a base such as potassium carbonate in acetone with heating e.g. at reflux.

Phenols of formula (IXb), wherein R1 is H and R2 is a C1-4 alkoxy group (R5 is a C1-4 alkyl group) can be prepared by monoalkylation from the compounds of formula (XIII) using for example the suitable iodo-alkyl in presence of a base such as potassium hydroxide in a solvent such as ethanol.

Step (iii):
Compounds of formula (Ia), corresponding to compounds of formula (I) wherein X=G, Y═C can be prepared from compounds of formula (XIV) by heating e.g. at 100° C. in aqueous HCl.
Step (ii):
Compounds of formula (XIV) can be prepared from isocyanates of formula (XV) wherein X═C, Y═C by addition of aminoacids of formula (VI) in presence of a base e.g. DIPEA in a solvent e.g. THF for example at room temperature.
Step (i):
Some isocyanates of formula (XV) are commercially available other ones can be prepared from anilines of formula (IVb) using triphosgene and optionally triethylamine in a solvent such as dichloromethane at room temperature. Anilines (IVb) corresponding to anilines of formula (IV) with X═C, Y═C can be prepared with similar conditions to the ones described previously.
Optionally the two steps (ii) and (ill) can be performed in a one pot fashion; in a first time, an addition of isocyanates (XV) over aminoacides of formula (VI) in presence of a base e.g. pyridine or trietylamine in a solvent e.g. N,N-dimethylformamide or a mixture dichloromethane/DMF (e.g. at 35° C.), then in a second time addition of HCl with heating (e.g. at 100° C.). Isocyanates can be prediluted in a solvent or not e.g. in THF.

Compounds of formula (Ib) corresponding to compounds of formula (I) wherein X═C, Y═C and R3═H can be prepared from anilines (IVb) [corresponding to anilines of formula (IV) wherein X═C, Y═C] in a one pot protocol.
In a first time, amino ester of formula (XVI) can be N-protected by a Boc group by reaction with Boc-anhydride in presence of a base e.g. DMAP in a solvent e.g. dichloromethane, in a second time, this solution can react with anilines (IVb) with heating e.g. at 35° C. and in a third time the cyclization can be promoted by addition of HCl and heating e.g. at 100° C.

Step (ii):
A nucleophilic substitution can be used to prepare compounds of formula (Ic) corresponding to compounds of formula (I) wherein X═N, Y═C R3═R4=Me and (R1, R2) are combinations of groups such as for example (p-CN, m-iRr), (H, m-OGF3), (p-F, m.CH3), (p-F, o-CH3), (p-CN, m-Cl), (p-CN, o-Et), (p-Me, m-OCF3), (p-CN, m-OMe). This reaction uses the corresponding phenol of formula (IXc), a fluoro compound of formula (XVII) in presence of a base e.g. potassium carbonate heating e.g. at 120° C. in a high boiling point solvent e.g. DMF.
Step (i):
Fluoro compound of formula (XVII) can be prepared by N-arylation of 5,5-dimethyl-2,4-imidazolidinedione (XVIII) with the arylboronic acid (XIX), promoted for example by copper (SI) acetate using a base e.g. pyridine and a solvent such as dichloromethane e.g. at room temperature, open to air.

Step (ii):
Compounds of formula (Id) corresponding to compounds of formula (I) wherein X═N, Y═C or X═C, Y═C or X═N, Y═N and R3═R4=Me can be prepared from ureas of formula (XXa) by cyclization in presence of a base e.g. sodium methoxide heating e.g. at 65° C. In solvent such as methanol.
Step (a):
Ureas of formula (XXa) can be prepared by addition of a solution containing an aniline of formula (IVc) (corresponding to anilines of formula IV wherein X═N, Y═C or X═C, Y═C or X═N, Y═N) and a base such as triethylamine in a solvent such as EtOAc to a solution of a carbonylating agent such as triphosgene in a solvent such as EtOAc e.g. at 0° C., followed by addition of triethylamine and ester (XXIa). Optionally, the ester (XXIa) can be pre-dissolved in a solvent such as EtOAc, the triethylamine being added to this pre-solution. Optionally some additional triethylamine and ester (XXIa) or some additional triphosgene can be added. The needed ester (XXIa) can be prepared from the corresponding aminoacid, using methanol, heating the reaction mixture e.g. at reflux, after thionyl chloride addition.

Step (ii):
Compounds of formula (Ie) corresponding to compounds of formula (I) wherein X=M, Y═C or X═C, Y═C or X═N, Y═N and R3=Me, R4=Et can be prepared from ureas of formula (XXb) by cyclization in presence of a base e.g. sodium methoxide heating e.g. at 65° C. in solvent such as methanol.
Step (i):
Ureas of formula (XXb) can be prepared by addition of a solution containing an aniline of formula (IVc) (corresponding to anilines of formula IV wherein X═N, Y═C or X═C, Y═C or X═N, Y═N) and a base such as triethylamine or diisopropylethylamine in a solvent such as EtOAc or dichloromethane to a solution of a carbonylating agent such as triphosgene in a solvent such as EtOAc or dichloromethane e.g. at 0° C., followed by addition of triethylamine or diisopropylethylamine and ester (XXIb). Optionally, the ester (XXIb) can be pre-dissolved in a solvent such as EtOAc or dichloromethane, the triethylamine or diisopropylethylamine being added to this pre-solution. Optionally some additional triethylamine or diisopropylethylamine and ester (XXIb) or some additional triphosgene can be added. The needed ester (XXIb) can be prepared from the corresponding aminoacid, using methanol, heating the reaction mixture e.g. at reflux, after thionyl chloride addition.

Step (iii):
Phenols of formula (IX) can be prepared from compounds of formula (XXII) by removal of the benzyl group for example in presence of hydrogen (e.g. P=1 atm) with a catalyst such as Pd/G in a solvent such as methanol, a mixture of ethylacetate/ethanol etc.
Step (ii):
Compounds of formula (XXIIa) corresponding to compounds of formula (XXII) wherein [R1; R2] are for example [(p-CN; o-Me or o-Et) or (p-Me or p-Et; m-OCF3)] can be prepared by Negishi coupling using the suitable pre-formed organozinc intermediate in solution (e.g. in THF) then Pd(tBu3P)2 and the corresponding bromo compound (XXIII) in a solvent such as THF. The organozinc intermediate can be prepared by addition of a solution of zinc bichloride on the suitable alkyl magnesium bromide solution or by reverse addition of the alkyl magnesium bromide solution on the zinc dichloride solution e.g. at −15° C., 0° C. or r.t. in solvents such as THF, diethyl ether. A solution of the bromo compound (XXIII) e.g. in THF can be added e.g. at 0° C. to the organozinc intermediate or reversely the organozinc intermediate solution can be added to a solution of the bromo compound (XXIII) pre-warmed e.g. at 60° C. Optionally some additional Pd(tBu3P)2 or some additional pre-formed organozinc intermediate can be added.
Step (i):
Bromo compound of formula (XXIII) can be prepared from compounds of formula (XXIV) by benzylation with benzylhalide e.g. benzyl bromide in presence of a base e.g. potassium carbonate, in a solvent such as acetone heating e.g. at 5° C., Scheme 16

Compounds of formula (Vile) [corresponding to compounds of formula (VII) wherein X═N, Y═C or X═N, Y═N, R1═CN and R2=meta- or ortho-(Me, Et or cyclopropyl)] can be prepared by Negishi coupling using the suitable pre-formed organozinc intermediate in solution (e.g. in THF) then Pd(tBu3P)2 and the corresponding halo compounds (VIId) [corresponding to compounds of formula (VII) wherein R1═CN and R2=meta- or ortho-halogen such as bromine and iodine)] in a solvent such as THF. The organozinc intermediate can be prepared by addition of a solution of zinc dichloride on the suitable alkyl magnesium bromide solution or by reverse addition of the alkyl magnesium bromide solution on the zinc dichloride solution e.g. at −15° C., 0° C. or room temperature in solvents such as THF, diethyl ether. A solution of the halo compound (VIId) e.g. in THF can be added e.g. at 0° C. to the organozinc intermediate or reversely the organozinc intermediate solution can be added to a solution of the halo compound (VIId) pre-warmed e.g. at 6° C. Optionally some additional Pd(tBu3P)2 or some additional pre-formed organozinc intermediate can be added.

Compounds of formula (XXV) wherein X═N, Y═C, R1=para-CN and R5=meta-(cyclopropyl), meta-isopropenyl] can be prepared by Suzuki coupling using the corresponding boronic acid or boronic ester, a base such as potassium triphosphate, a system containing a palladium catalyst and a ligand such as (Pd(OAc)2/PCy3) or (Pd(tBu3)2, in a solvent such as DMF, a mixture (toluene/water) etc heating e.g. at 110° C. optionally under microwave irradiation.

Phenol of formula (IXc) [corresponding to compound of formula (IX) wherein R1=para-CN and R6=meta-I or ortho-Me] can be prepared from fluoroaromatics of formula (XXVI), using potassium trimethylsilanolate and heating e.g. at a temperature ranging from r.t. to 70° C. in a solvent such as acetonitrile.

Step ii:
Phenol of formula (Ixd) [corresponding to compound of formula (IX) wherein R1=para-GN and R2=ortho-tBu] can be prepared from compounds of formula (XXVII) using hydroxylamine hydrochloride in acetic acid, heating e.g. at reflux.
Step i:
Compound of formula (XXVII) can be prepared by a Reimer-Tiemann formylation starting from compound of formula (XXVIII) in a solvent such as a mixture MeOH/water, using an hydroxide base such as sodium hydroxide in water, heating e.g. at 6° C. and adding chloroform.

Step ii:
Compounds of formula (VIIf) [corresponding to compounds of formula (VII) wherein X═C, Y═N or X═C, Y=G and R1=para-CN and R2═OR7 with R7═C1-4 alkyl] can be prepared from compounds of formula (XXIX) using as alkylating agent a suitable halo derivative, a base such as potassium carbonate in a solvent such as DMF e.g. at temperature ranging from r.t. to 60°
Step i:
Compounds of formula (XXIX) can be prepared from compounds of formula (XXX) and electrophiles (VIII), wherein Z═F or Cl in a similar manner to the one described in scheme 5.

Phenol of formula (IXe) can be prepared from compound of formula (XXXI), using a demethylating agent such a BBr3, in a solvent such as dichlorometane or dichloroethane at a suitable temperature ranging from r.t. to 100° C. optionally under microwave irradiation.

Step iii:
Compounds of formula (IIIa) [corresponding to compounds of formula (III) wherein X═C, Y═N and R1=para-CN and R2=iPr] can be prepared from compounds of formula (XXXII) by reduction with hydrogen (P=1 atm) in presence of a catalyst such as Pd/C, in a solvent such as methanol.
Step ii, i:
Compounds of formula (XXXII) can be prepared in 2 steps from nitro compounds of formula (XXXIII) using a similar way to the one described on schemes 3, 2 (e.g. reduction with Fe/ammonium chloride and coupling).

Step i:
Compounds of formula (XXXIV) wherein X═N, Y═N can be prepared by Suzuki coupling using the methyl boronic acid, a base such as potassium triphosphate, a system containing a palladium catalyst and a ligand such as (Pd(OAc)2/PCy3) or (Pd(tBu3)2) in a solvent such as DMF heating e.g. at 110° C. optionally under microwave irradiation.

Step i:
Compounds of formula (ie) can be prepared from compounds of formula (XXXV) by reduction with hydrogen (P=1 atm) in presence of a catalyst such as Pd/G, in a solvent such as methanol.
The present invention provides compounds of formula (I) or a pharmaceutically acceptable salt thereof for use in therapy.
The compounds of formula (i) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of a disease or disorder where a modulator of the Kv3.1 or Kv3.2 or Kv3.1 and Kv3.2 channels is required. As used herein, a modulator of Kv3.1 or Kv3.2 or Kv 3.1 and Kv3.2 is a compound which alters the properties of these channels, either positively or negatively.
Diseases or conditions that may be mediated by modulation of Kv3.1 and/or Kv3.1 channels may be selected from the list below. The numbers in brackets after the listed diseases below refer to the classification code in Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, published by the American Psychiatric Association (DSM-IV) and/or the International Classification of Diseases, 10th Edition (ICD-10).
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of depression and mood disorders including Major Depressive Episode, Manic Episode, Mixed Episode and Hypomanic Episode; Depressive Disorders including Major Depressive Disorder, Dysthymic Disorder (300.4), Depressive Disorder Not Otherwise Specified (311); Bipolar Disorders including Bipolar I Disorder, Bipolar II Disorder (Recurrent Major Depressive Episodes with Hypomanic Episodes) (296.89), Cyclothymic Disorder (301.13) and Bipolar Disorder Not Otherwise Specified (296.80); Other Mood Disorders including Mood Disorder Due to a General Medical Condition (293.83) which includes the subtypes With Depressive Features, With Major Depressive-like Episode, With Manic Features and With Mixed Features), Substance-Induced Mood Disorder (including the subtypes With Depressive Features, With Manic Features and With Mixed Features) and Mood Disorder Not Otherwise Specified (296.90); Seasonal affective disorder.
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of schizophrenia including the subtypes Paranoid Type (295.30), Disorganised Type (295.10), Catatonic Type (295.20), Undifferentiated Type (295.90) and Residual Type (295.60); Schizophreniform Disorder (295.40); Schizoaffective Disorder (295.70) including the subtypes Bipolar Type and Depressive Type; Delusional Disorder (297.1) including the subtypes Erotomania Type, Grandiose Type, Jealous Type, Persecutory Type, Somatic Type, Mixed Type and Unspecified Type; Brief Psychotic Disorder (298.8); Shared Psychotic Disorder (297.3); Psychotic Disorder Due to a General Medical Condition including the subtypes With Delusions and With Hallucinations; Substance-induced Psychotic Disorder including the subtypes With Delusions (293.81) and With Hallucinations (293.82); and Psychotic Disorder Not Otherwise Specified (298.9).
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of anxiety disorders including Panic Attack; Panic Disorder including Panic Disorder without Agoraphobia (300.01) and Panic Disorder with Agoraphobia (300.21); Agoraphobia; Agoraphobia Without History of Panic Disorder (300.22), Specific Phobia (300.29, formerly Simple Phobia) including the subtypes Animal Type, Natural Environment Type, Blood-Injection-Injury Type, Situational Type and Other Type), Social Phobia (Social Anxiety Disorder, 300.23), Obsessive-Compulsive Disorder (300.3), Posttraumatic Stress Disorder (309.81), Acute Stress Disorder (308.3), Generalized Anxiety Disorder (300.02), Anxiety Disorder Due to a General Medical Condition (293.84), Substance-Induced Anxiety Disorder, Separation Anxiety Disorder (309.21), Adjustment Disorders with Anxiety (309.24) and Anxiety Disorder Not Otherwise Specified (300.00):
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of substance-related disorders including Substance Use Disorders such as Substance Dependence, Substance Craving and Substance Abuse; Substance-Induced Disorders such as Substance Intoxication, Substance Withdrawal, Substance-induced Delirium, Substance-Induced Persisting Dementia, Substance-Induced Persisting Amnestic Disorder, Substance-induced Psychotic Disorder, Substance-Induced Mood Disorder, Substance-Induced Anxiety Disorder, Substance-Induced Sexual Dysfunction, Substance-Induced Sleep Disorder and Hallucinogen Persisting Perception Disorder (Flashbacks); Alcohol-Related Disorders such as Alcohol Dependence (303.90), Alcohol Abuse (305.00), Alcohol intoxication (303.00), Alcohol Withdrawal (291,81), Alcohol Intoxication Delirium, Alcohol Withdrawal Delirium, Alcohol-Induced Persisting Dementia, Alcohol-Induced Persisting Amnestic Disorder, Alcohol-Induced Psychotic Disorder, Alcohol-induced Mood Disorder, Alcohol-Induced Anxiety Disorder, Alcohol-Induced Sexual Dysfunction, Alcohol-Induced Sleep Disorder and Alcohol-Related Disorder Not Otherwise Specified (2919); Amphetamine (or Amphetamine-Like)-Related Disorders such as Amphetamine Dependence (304.40), Amphetamine Abuse (305.70), Amphetamine Intoxication (292.89), Amphetamine Withdrawal (292.0), Amphetamine Intoxication Delirium, Amphetamine Induced Psychotic Disorder, Amphetamine-Induced Mood Disorder, Amphetamine-Induced Anxiety Disorder, Amphetamine-Induced Sexual Dysfunction, Amphetamine-Induced Sleep Disorder and Amphetamine-Related Disorder Not Otherwise Specified (292.9); Caffeine Related Disorders such as Caffeine intoxication (305.90), Caffeine-Induced Anxiety Disorder, Caffeine-Induced Sleep Disorder and Caffeine-Related Disorder Not Otherwise Specified (292.9); Cannabis-Related Disorders such as Cannabis Dependence (304.30), Cannabis Abuse (305.20), Cannabis Intoxication (292.89), Cannabis Intoxication Delirium, Cannabis-Induced Psychotic Disorder, Cannabis-Induced Anxiety Disorder and Cannabis-Related Disorder Not Otherwise Specified (292.9); Cocaine-Related Disorders such as Cocaine Dependence (304.20), Cocaine Abuse (305.80), Cocaine Intoxication (292.89), Cocaine Withdrawal (292.0), Cocaine Intoxication Delirium, Cocaine-Induced Psychotic Disorder, Cocaine-Induced Mood Disorder, Cocaine-induced Anxiety Disorder, Cocaine-Induced Sexual Dysfunction, Cocaine-induced Sleep Disorder and Cocaine-Related Disorder Not Otherwise Specified (292.9); Hallucinogen-Related Disorders such as Hallucinogen Dependence (304.50), Hallucinogen Abuse (305.30), Hallucinogen Intoxication (292.89), Hallucinogen Persisting Perception Disorder (Flashbacks) (292.89), Hallucinogen Intoxication Delirium, Hallucinogen-Induced Psychotic Disorder, Hallucinogen-Induced Mood Disorder, Hallucinogen-Induced Anxiety Disorder and Hallucinogen-Related Disorder Not Otherwise Specified (292.9); Inhalant-Related Disorders such as inhalant Dependence (304.60), inhalant Abuse (305.90), Inhalant Intoxication (292.89), inhalant Intoxication Delirium, inhalant-induced Persisting Dementia, inhalant-induced Psychotic Disorder, Inhalant-Induced Mood Disorder, Inhalant-Induced Anxiety Disorder and Inhalant-Related Disorder Not Otherwise Specified (292.9); Nicotine-Related Disorders such as Nicotine Dependence (305.1), Nicotine Withdrawal (292.0) and Nicotine-Related Disorder Not Otherwise Specified (292.9); Opioid-Related Disorders such as Opioid Dependence (304.00), Opioid Abuse (305.50), Opioid Intoxication (292.89), Opioid Withdrawal (292.0), Opioid Intoxication Delirium, Opioid-Induced Psychotic Disorder, Opioid-Induced Mood Disorder, Opioid-Induced Sexual Dysfunction, Opioid-Induced Sleep Disorder and Opioid-Related Disorder Not Otherwise Specified (292.9); Phencyclidine (or Phencyclidine-Like)-Related Disorders such as Phencyclidine Dependence (304.60), Phencyclidine Abuse (305.90), Phencyclidine Intoxication (292.89), Phencyclidine Intoxication Delirium, Phencyclidine-Induced Psychotic Disorder, Phencyclidine-Induced Mood Disorder, Phencyclidine-Induced Anxiety Disorder and Phencyclidine-Related Disorder Not Otherwise Specified (292.9); Sedative-, Hypnotic-, or Anxiolytic-Related Disorders such as Sedative, Hypnotic, or Anxiolytic Dependence (304.10), Sedative, Hypnotic, or Anxiolytic Abuse (305.40), Sedative, Hypnotic, or Anxiolytic Intoxication (292.89), Sedative, Hypnotic, or Anxiolytic Withdrawal (292.0), Sedative, Hypnotic, or Anxiolytic Intoxication Delirium, Sedative, Hypnotic, or Anxiolytic Withdrawal Delirium, Sedative-, Hypnotic-, or Anxiolytic-Persisting Dementia, Sedative-, Hypnotic-, or Anxiolytic-Persisting Amnestic Disorder, Sedative-, Hypnotic-, or Anxiolytic-Induced Psychotic Disorder, Sedative-, Hypnotic-, or Anxiolytic-Induced Mood Disorder, Sedative-, Hypnotic-, or Anxiolytic-Induced Anxiety Disorder Sedative-, Hypnotic-, or Anxiolytic-Induced Sexual Dysfunction, Sedative-, Hypnotic-, or Anxiolytic-Induced Sleep Disorder and Sedative-, Hypnotic-, or Anxiolytic-Related Disorder Not Otherwise Specified (292.9); Polysubstance-Related Disorder such as Polysubstance Dependence (304.80); and Other (or Unknown) Substance-Related Disorders such as Anabolic Steroids, Nitrate inhalants and Nitrous Oxide: The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of enhancement of cognition including the treatment of cognition impairment in other diseases such as schizophrenia, bipolar disorder, depression, other psychiatric disorders and psychotic conditions associated with cognitive impairment, e.g. Alzheimer's disease.
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of sleep disorders including primary sleep disorders such as Dyssomnias such as Primary Insomnia (307.42), Primary Hypersomnia (307.44), Narcolepsy (347), Breathing-Related Sleep Disorders (780.59), Circadian Rhythm Sleep Disorder (307.45) and Dyssomnia Not Otherwise Specified (307.47); primary sleep disorders such as Parasomnias such as Nightmare Disorder (307.47), Sleep Terror Disorder (307.46), Sleepwalking Disorder (307.46) and Parasomnia Not Otherwise Specified (307.47); Sleep Disorders Related to Another Mental Disorder such as Insomnia Related to Another Mental Disorder (307.42) and Hypersomnia Related to Another Mental Disorder (307.44); Sleep Disorder Due to a General Medical Condition, in particular sleep disturbances associated with such diseases as neurological disorders, neuropathic pain, restless leg syndrome, heart and lung diseases; and Substance-induced Sleep Disorder including the subtypes Insomnia Type, Hypersomnia Type, Parasomnia Type and Mixed Type; sleep apnea and jet-lag syndrome:
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of eating disorders such as Anorexia Nervosa (307.1) including the subtypes Restricting Type and Binge-Eating/Purging Type; Bulimia Nervosa (307.51) including the subtypes Purging Type and Nonpurging Type; Obesity; Compulsive Eating Disorder; Binge Eating Disorder; and Eating Disorder Not Otherwise Specified (307.50):
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Autism Spectrum Disorders including Autistic Disorder (299.00), Asperger's Disorder (299.80), Rett's Disorder (299.80), Childhood Disintegrative Disorder (299.10) and Pervasive Disorder Not Otherwise Specified (299.80, including Atypical Autism).
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Attention-Deficit/Hyperactivity Disorder including the subtypes Attention-Deficit/Hyperactivity Disorder Combined Type (314.01), Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Type (314.00), Attention-Deficit/Hyperactivity Disorder Hyperactive-Impulse Type (314.01) and Attention-Deficit/Hyperactivity Disorder Not Otherwise Specified (314.9); Hyperkinetic Disorder; Disruptive Behaviour Disorders such as Conduct Disorder including the subtypes childhood-onset type (321.81), Adolescent-Onset Type (312.82) and Unspecified Onset (312.89), Oppositional Defiant Disorder (313.81) and Disruptive Behaviour Disorder Not Otherwise Specified; and Tic Disorders such as Tourette's Disorder (307.23):
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Personality Disorders including the subtypes Paranoid Personality Disorder (301.0), Schizoid Personality Disorder (301.20), Schizotypal Personality Disorder (301.22), Antisocial Personality Disorder (301.7), Borderline Personality Disorder (301.83), Histrionic Personality Disorder (301.50), Narcissistic Personality Disorder (301.81), Avoidant Personality Disorder (301.82), Dependent Personality Disorder (301.6), Obsessive-Compulsive Personality Disorder (301.4) and Personality Disorder Not Otherwise Specified (301.9).
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Sexual dysfunctions including Sexual Desire Disorders such as Hypoactive Sexual Desire Disorder (302.71), and Sexual Aversion Disorder (302.79); sexual arousal disorders such as Female Sexual Arousal Disorder (302.72) and Male Erectile Disorder (302.72); orgasmic disorders such as Female Orgasmic Disorder (302.73), Male Orgasmic Disorder (302.74) and Premature Ejaculation (302.75); sexual pain disorder such as Dyspareunia (302.76) and Vaginismus (306.51); Sexual Dysfunction Not Otherwise Specified (302.70); paraphilias such as Exhibitionism (302.4), Fetishism (302.81), Frotteurism (302.89), Pedophilia (302.2), Sexual Masochism (302.83), Sexual Sadism (302.84), Transvestic Fetishism (302.3), Voyeurism (302.82) and Paraphilia Not Otherwise Specified (302.9); gender identity disorders such as Gender Identity Disorder in Children (302.6) and Gender Identity Disorder in Adolescents or Adults (302.85); and Sexual Disorder Not Otherwise Specified (302.9).
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Impulse control disorder” including: Intermittent Explosive Disorder (312.34), Kleptomania (312.32), Pathological Gambling (312.31), Pyromania (312.33), Trichotillomania (312.39), Impulse-Control Disorders Not Otherwise Specified (312.3), Binge Eating, Compulsive Buying, Compulsive Sexual Behaviour and Compulsive Hoarding.
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of hearing disorders including auditory neuropathy, auditory processing disorder, hearing loss, which includes sudden hearing loss, noise induced hearing loss, substance-induced hearing loss, and hearing loss in adults over 60 (presbycusis), and tinnitus.
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Ménieré's disease, disorders of balance, and disorders of the inner ear.
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of hyperacusis and disturbances of loudness perception, including Fragile-X syndrome and autism.
The compounds of formula (I) or their pharmaceutically acceptable salts may be of use for the treatment or prophylaxis of Epilepsy, (including, but not limited to, localization-related epilepsies, generalized epilepsies, epilepsies with both generalized and local seizures, and the like), seizures associated with Lennox-Gastaut syndrome, seizures as a complication of a disease or condition (such as seizures associated with encephalopathy, phenylketonuria, juvenile Gaucher's disease, Lundborg's progressive myoclonic epilepsy, stroke, head trauma, stress, hormonal changes, drug use or withdrawal, alcohol use or withdrawal, sleep deprivation, fever, infection, and the like), essential tremor, restless limb syndrome, partial and generalised seizures (including tonic, clonic, tonic-clonic, atonic, myoclonic, absence seizures), secondarily generalized seizures, temporal lobe epilepsy, absence epilepsies (including childhood, juvenile, myoclonic, photo- and pattern-induced), severe epileptic encephalopathies (including hypoxia-related and Rasmussen's syndrome), febrile convulsions, epilepsy partialis continua, progressive myoclonus epilepsies (including Unverricht-Lundborg disease and Lafora's disease), post-traumatic seizures/epilepsy including those related to head injury, simple reflex epilepsies (including photosensive, somatosensory and proprioceptive, audiogenic and vestibular), metabolic disorders commonly associated with epilepsy such as pyridoxine-dependent epilepsy, Menkes' kinky hair disease, Krabbe's disease, epilepsy due to alcohol and drug abuse (e.g. cocaine), cortical malformations associated with epilepsy (e.g. double cortex syndrome or subcortical band heterotopia), chromosomal anomolies associated with seizures or epilepsy such as Partial monosomy (15Q)/Angelman syndrome)
and the like.
In one embodiment of the invention, there is provided a compound of formula (I) or a pharmaceutically acceptable salt thereof for the treatment or prophylaxis of depression and mood disorders, hearing disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy.
In one embodiment of the invention, there is provided a compound of formula (I) or a pharmaceutically acceptable salt thereof for the treatment or prophylaxis of bipolar disorder or mania.
The term “treatment” or “treating” as used herein includes the control, mitigation, reduction, or modulation of the disease state or its symptoms.
The term “prophylaxis” is used herein to mean preventing symptoms of a disease or disorder in a subject or preventing recurrence of symptoms of a disease or disorder in an afflicted subject and is not limited to complete prevention of an affliction.
The invention also provides a method of treating or preventing a disease or disorder where a modulator of Kv3 is required, for example those diseases and disorders mentioned hereinabove, which comprises administering to a subject in need thereof an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.
The invention also provides a compound of formula (I), or a pharmaceutically acceptable salt thereof, for use in the treatment or prophylaxis of a disease or disorder where a modulator of Kv3 is required, for example those diseases and disorders mentioned hereinabove.
The invention also provides the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for the treatment or prophylaxis of a disease or disorder where a modulator of Kv3 is required, for example those diseases and disorders mentioned hereinabove.
The invention also provides a method of treating depression and mood disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy, for example for those indications mentioned hereinabove, which comprises administering to a subject in need thereof an effective amount of a Kv3 modulator or a pharmaceutically acceptable salt thereof.
For use in therapy the compounds of the invention are usually administered as a pharmaceutical composition. The invention also provides a pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.
The compounds of formula (I) or their pharmaceutically acceptable salts may be administered by any convenient method, e.g. by oral, parenteral, buccal, sublingual, nasal, rectal or transdermal administration, and the pharmaceutical compositions adapted accordingly.
The compounds of formula (I) or their pharmaceutically acceptable salts which are active when given orally can be formulated as liquids or solids, e.g. as syrups, suspensions, emulsions, tablets, capsules or lozenges.
A liquid formulation will generally consist of a suspension or solution of the active ingredient in a suitable liquid carrier(s) e.g. an aqueous solvent such as water, ethanol or glycerine, or a non-aqueous solvent, such as polyethylene glycol or an oil. The formulation may also contain a suspending agent, preservative, flavouring and/or colouring agent.
A composition in the form of a tablet can be prepared using any suitable pharmaceutical carrier(s) routinely used for preparing solid formulations, such as magnesium stearate, starch, lactose, sucrose and cellulose.
A composition in the form of a capsule can be prepared using routine encapsulation procedures, e.g. pellets containing the active ingredient can be prepared using standard carriers and then filled into a hard gelatin capsule; alternatively a dispersion or suspension can be prepared using any suitable pharmaceutical carrier(s), e.g. aqueous gums, celluloses, silicates or oils and the dispersion or suspension then filled into a soft gelatin capsule.
Typical parenteral compositions consist of a solution or suspension of the active ingredient in a sterile aqueous carrier or parenterally acceptable oil, e.g. polyethylene glycol, polyvinyl pyrrolidone, lecithin, arachis oil or sesame oil. Alternatively, the solution can be lyophilised and then reconstituted with a suitable solvent just prior to administration.
Compositions for nasal administration may conveniently be formulated as aerosols, drops, gels and powders. Aerosol formulations typically comprise a solution or fine suspension of the active ingredient in a pharmaceutically acceptable aqueous or non-aqueous solvent and are usually presented in single or multidose quantities in sterile form in a sealed container which can take the form of a cartridge or refill for use with an atomising device. Alternatively the sealed container may be a disposable dispensing device such as a single dose nasal inhaler or an aerosol dispenser fitted with a metering valve. Where the dosage form comprises an aerosol dispenser, it will contain a propellant which can be a compressed gas e.g. air, or an organic propellant such as a fluorochloro-hydrocarbon or hydrofluorocarbon. Aerosol dosage forms can also take the form of pump-atomisers.
Compositions suitable for buccal or sublingual administration include tablets, lozenges and pastilles where the active ingredient is formulated with a carrier such as sugar and acacia, tragacanth, or gelatin and glycerin.
Compositions for rectal administration are conveniently in the form of suppositories containing a conventional suppository base such as cocoa butter.
Compositions suitable for transdermal administration include ointments, gels and patches.
In one embodiment the composition is in unit dose form such as a tablet, capsule or ampoule.
The composition may contain from 0.1% to 100% by weight, for example from 10 to 60% by weight, of the active material, depending on the method of administration. The composition may contain from 0% to 99% by weight, for example 40% to 90% by weight, of the carrier, depending on the method of administration. The composition may contain from 0.05 mg to 1000 mg, for example from 1.0 mg to 500 mg, of the active material, depending on the method of administration. The composition may contain from 50 mg to 1000 mg, for example from 100 mg to 400 mg of the carrier, depending on the method of administration. The dose of the compound used in the treatment of the aforementioned disorders will vary in the usual way with the seriousness of the disorders, the weight of the sufferer, and other similar factors. However, as a general guide suitable unit doses may be 0.05 to 1000 mg, more suitably 1.0 to 500 mg, and such unit doses may be administered more than once a day, for example two or three a day. Such therapy may extend for a number of weeks or months.
The invention provides, in a further aspect, a combination comprising a compound of formula (I) or a pharmaceutically acceptable derivative thereof together with a further therapeutic agent or agents.
When the compounds are used in combination with other therapeutic agents, the compounds may be administered either sequentially or simultaneously by any convenient route.
The combinations referred to above may conveniently be presented for use in the form of a pharmaceutical formulation and thus pharmaceutical formulations comprising a combination as defined above together with a pharmaceutically acceptable carrier or excipient comprise a further aspect of the invention. The individual components of such combinations may be administered either sequentially or simultaneously in separate or combined pharmaceutical formulations.
When a compound of formula (I) or a pharmaceutically acceptable derivative thereof is used in combination with a second therapeutic agent active against the same disease state the dose of each compound may differ from that when the compound is used alone. Appropriate doses will be readily appreciated by those skilled in the art.
A pharmaceutical composition of the invention, which may be prepared by admixture, suitably at ambient temperature and atmospheric pressure, is usually adapted for oral, parenteral or rectal administration and, as such, may be in the form of tablets, capsules, oral liquid preparations, powders, granules, lozenges, reconstitutable powders, injectable or infusible solutions or suspensions or suppositories. Orally administrable compositions are generally preferred.
The present invention also provides Kv3 modulators, or their pharmaceutically acceptable salts, for use in the treatment or prophylaxis of depression and mood disorders, hearing disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy.
In particular Kv3 modulators or their pharmaceutically acceptable salts may be particularly useful in the treatment or prophylaxis of depression and mood disorders including Major Depressive Episode, Manic Episode, Mixed Episode and Hypomanic Episode; Depressive Disorders including Major Depressive Disorder, Dysthymic Disorder (300.4), Depressive Disorder Not Otherwise Specified (311); Bipolar Disorders including Bipolar I Disorder, Bipolar II Disorder (Recurrent Major Depressive Episodes with Hypomanic Episodes) (296.89), Cyclothymic Disorder (301.13) and Bipolar Disorder Not Otherwise Specified (296.80); Other Mood Disorders including Mood Disorder Due to a General Medical Condition (293.83) which includes the subtypes With Depressive Features, With Major Depressive-like Episode, With Manic Features and With Mixed Features), Substance-Induced Mood Disorder (including the subtypes With Depressive Features, With Manic Features and With Mixed Features) and Mood Disorder Not Otherwise Specified (296.90), Seasonal affective disorder
The invention also provides a method of treating depression and mood disorders, hearing disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy, including for example those disorders mentioned hereinabove, which comprises administering to a subject in need thereof an effective amount of Kv3 modulator or a pharmaceutically acceptable salt thereof.
The invention also provides a Kv3 modulator, or a pharmaceutically acceptable salt thereof, for use in the treatment or prophylaxis of depression and mood disorders, hearing disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy, including for example those disorders mentioned hereinabove.
The invention also provides the use of a Kv3 modulator, or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for the treatment or prophylaxis of depression and mood disorders, hearing disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy, including for example those disorders mentioned hereinabove.
For use in therapy the Kv3 modulators are usually administered as a pharmaceutical composition for example a composition comprising a Kv3 modulator or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier. Examples of such compositions, and methods of administration thereof, which compositions comprise a compound of formula (I) or a pharmaceutically acceptable salt thereof, are described hereinabove. Such compositions and methods of administration may also be used for other Kv3 modulators or pharmaceutically acceptable salts thereof, in the treatment of depression and mood disorders, hearing disorders, schizopherenea, substance abuse disorders, sleep disorders or epilepsy, including for example those disorders mentioned hereinabove.
All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.